Influence of sex and body size on selected morphometric traits of Metopograpsus frontalis (Miers, 1880) from Southern Vietnam

A total of 167 specimens of Metopograpsus frontalis (105 males and 62 females) were collected monthly from intertidal mudflats in Ganh Hao, Ca Mau Province, Southern Vietnam, from July to October 2025. Selected morphometric traits, including carapace width from left to right (CWL–R), carapace width from right to left (CWR–L), manus width (MW2, MW3), pollex width (PW5), and dactyl width (DW7), were measured with a 0.01-mm vernier caliper. Generalized linear models were fitted to evaluate the effects of sex and body size, using Gaussian models for CW and Gamma models with a log link for MW, PW, and DW. We found no significant sex-related differences in CWL–R and CWR–L (p > 0.05), whereas MW2, MW3, PW5, and DW7 were significantly larger in males (p